For 8 days of very hot weather, the water level in a lake dropped 3 inches per day. on the ninth day, storms raised the level 6 inches. write and find the value of an expression for the change in the water level of the lake during these 9 days.

Hi there!
Your question is:
For 8 days of very hot weather, the water level in a lake dropped 3 inches per day. on the ninth day, storms raised the level 6 inches. Write and find the value of an expression for the change in the water level of the lake during these 9 days.Here is my

If the water level drops 3 inches per day for eight days, it would have gone down a total of 24 inches over those 8 days. Now, the rain storm added 9 inches of water back to the lake. 24 - 9 = 15. 
Summary:
8 x 3 = 24
-24 + 9 = -15.

I hope this helped you, and dont hesitate to ask me for anymore help if you need it.

Stay Cray! xD